Photophysics photophysical studies

The importance of the particle levitation methods is that they allow the study of how a single particle responds to changes in environment. The infrared molecular spectroscopy of single particles is possible [253], as are photophysical studies using adsorbed or dissolved dyes. 

Liddell P A, Sumida J P, Macpherson A N, Noss L, Seely G R, Clark K N, Moore A L, Moore T A and Gust D 1994 Preparation and photophysical studies of porphyrin-Cgg dyads Photochem. Photobiol. 60 537-41... 

That dendrimers are unique when compared with other architectures is confirmed by an investigation on porphyrin core dendrimers and their isomeric linear analogues [63]. The isomers displayed dramatically different hydrodynamic properties, crystallinity, and solubility characteristics when compared to those of their dendritic analogues, and photophysical studies showed that energy transfer from the poly(benzylether) backbone to the core was more efficient in the dendrimer because of the shorter distance between the donor units and the acceptor core. 

Fernandez, F.J., Jones, P.G., Laguna, A., Lopez-de-Luzuriaga, J.M., Monge, M., Perez, J. and Olmos, M.E. (2002) Synthesis, Structure, and Photophysical Studies of Luminescent Two- and Three-Dimensional Gold-Thallium Supramolecular Arrays. Inorganic Chemistry, 41(5), 1056-1063. 

Photophysical Studies of Ultraviolet Stabilizers, Particularly in the 2-Hydroxyphenyl Benzotriazole Class... 

A typical ligand capable of generating a dendritic structure is 1,4,5,8,9,12-hexaazatriphenylene (HAT). Photophysical studies of trinuclear species based on HAT have been reported [14 a, 49]. Representative example of complexes of this type are 26, 27, and 28. For some of these complexes, the luminescence, originating from MLCT levels involving the central HAT ligand, was found to decay with multiexponential kinetics. Furthermore, the vibrational modes responsible for the nonradiative decay of the luminescent MLCT states are different in the polynuclear dendritic edifices with respect to the mononuclear [M(L)2(HAT)]2+ compounds [14a]. 

Photophysical studies have been performed on dendrimers 41 [49], built around a [Ru(bpm)3]2+ core (bpm=2,2 -bipyrimidine),and42 [59],built around a [Ru(QP)3]2+ core (QP = 2,2 3, 2" 6",2" -quaterpyridine). In both compounds energy transfer from the peripheral Re(I)-based chromophores to the central Ru(II)-based unit occurs with unitary efficiency. 

Whitaker JE, Haugland RP, Prendergast FG (1991) Spectral and photophysical studies of benzo[c]xanthenes dyes dual emission pH sensors. Anal Biochem 194 330-344... 

A.M. Sarker, E.E. Giirel, M. Zheng, P.M. Lahti, and F.E. Karasz, Synthesis, characterization, and photophysical studies of new blue-emitting segmented copolymers, Macromolecules, 34 5897-5901, 2001. 

The reaction mechanism for the aerobic oxidation of the pz to seco-pz can be attributed to a formal 2 + 2 cycloaddition of singlet oxygen to one of the pyrrole rings, followed by cleavage (retro 2 + 2) of the dioxetane intermediate to produce the corresponding seco-pz (160). This mechanism is shown in Scheme 29 for an unsymmetrical bis(dimethylamino)pz. Further photophysical studies show that the full reaction mechanism of the photoperoxidation involves attack on the reactant by singlet oxygen that has been sensitized by the triplet state of the product, 159. As a consequence, the kinetics of the process is shown to be autocatalytic where the reactant is removed at a rate that increases with the amount of product formed. 

Photophysical Studies of Spin-Cast Polymer Films... 

One of the first examples describing the idea of fluorescence signal amplification in NPs was reported by Montalti et al. [197]. In an early work, silicaNPs were covered with a layer of dansyl (Dns) moieties and were evaluated for their pH response. Photophysical studies indicated that protonation had a dramatic effect on the fluorescence of the NPs, leading to the quenching of both, the protonated Dns and... 

Letard JF, Lapouyade R, Rettig W (1993) Synthesis and photophysical study of 4-(N-monoaza-15-crown-5) stilbenes forming TICT states and their complexation with cations. Pure Appl Chem 65 1705-1712... 

Photophysical Studies of Molecular Mobility in Polymer Films and Bulk Polymers. 3. Dynamic Excimer Formation of Pyrene in Bulk PDMS, Macromolecules 23, 2217-2222. 

Whitaker J. E., Haugland R. P. and Prendergast F. G. (1991) Spectral and Photophysical Studies of Benzo[c]xanthene Dyes Dual Emission pH Sensors, Anal. Biochem. 194, 330—44. 

When, after a detailed photophysical study, all the characteristics of the ground and excited states prototropic reactions of a molecule are known, in return we have in hand a probe which can quantitatively monitor the pH of its microscopic surrounding. In fact, as a rule, the absorption and the fluorescence spectra of a probe are only measurably dependent on pH over ca. 2 pH units around its pKa-Since probes with a wide range of pKu values—currently from 1 to 9—are available, pH values from 0 to 10 are addressable. For multiple reasons fluorescence measurements are preferred to direct absorption spectra. 

J. E. Whitaker, R. P. Haugland, G. Predengast, Spectral and photophysical studies of benzo[c]xan-thene dyes Dual emission pH sensors, A nal. Biochem. 194, 330-344(1991). 

M. Masuhara, S. Tazuke, N. Tamai, and I. Yamazaki, Time-resolved total internal reflection fluorescence spectroscopy for surface photophysics studies, J. Phys. Chem. 90, 5830-5835 (1986). 

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